A physics teacher designs a rather unusual demonstration of simple harmonic motion which utilizes a combination of a 4.0 kg mass and two identical springs mounted on a smooth horizontal table. Each spring has a force constant of 75 N/m and an unstretched length of 0.25 m. The motion is started by releasing the mass from point A, where both springs have lengths of 0.5 m. One cycle is carried out as the mass moves from A to B to C to B to A. From the information given,
a. find the speed of the mass as it passes through the central point B.